A Ph Ib Study of REGN5678 Plus Cemiplimab in Patients With mCRPC
NCT ID: NCT06826768
Last Updated: 2025-12-18
Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.
RECRUITING
PHASE1
60 participants
INTERVENTIONAL
2025-07-09
2029-05-01
Brief Summary
Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.
Detailed Description
Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.
* To evaluate the safety and tolerability of REGN5678 (PSMAxCD28 bispecific antibody) plus cemiplimab (anti-PD-1) in patients with mCRPC.
* To determine the maximum tolerated dose or potential recommended phase II dose (RP2D) of REGN5678 (PSMAxCD28 bispecific antibody) plus cemiplimab (anti-PD-1) in patients with mCRPC
Secondary Objectives:
* To evaluate efficacy of REGN5678 plus cemiplimab in patients with mCRPC.
* To characterize the PK of REGN5678 alone and in combination with cemiplimab
* To assess the immunogenicity of REGN5678 and cemiplimab.
Exploratory Objective:
• To evaluate immune responses in the prostate TME and peripheral blood after treatment with REGN5678 plus cemiplimab as compared to pre-treatment samples.
Conditions
See the medical conditions and disease areas that this research is targeting or investigating.
Study Design
Understand how the trial is structured, including allocation methods, masking strategies, primary purpose, and other design elements.
NA
SINGLE_GROUP
TREATMENT
NONE
Study Groups
Review each arm or cohort in the study, along with the interventions and objectives associated with them.
Treatment with REGN5678 Q3W IV + Cemiplimab Q3W IV
Patients will receive three weekly doses of REGN5678 as part of a Lead-In Phase and thentransition to every three-week dosing of the combination of REGN5678 and cemiplimab (anti-PD-1).
REGN5678
Given by IV infusion
Cemiplimab
Given by IV infusion
Interventions
Learn about the drugs, procedures, or behavioral strategies being tested and how they are applied within this trial.
REGN5678
Given by IV infusion
Cemiplimab
Given by IV infusion
Eligibility Criteria
Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.
Inclusion Criteria
2. Histologically or cytologically confirmed adenocarcinoma of the prostate without pure small cell carcinoma.
3. mCRPC with disease progression after at least two lines of systemic therapy, including one line of second-generation anti-androgen therapy, according to one of the following criteria:
1. PSA progression as defined by a rising PSA level confirmed with an interval of \>1 week between each assessment.
2. Radiographic disease progression in soft tissue based on RECIST Version 1.1 criteria with PCWG3 modifications with or without PSA progression.
3. Radiographic disease progression in bone defined as the appearance of 2 or more new bone lesions on bone scan with or without PSA progression.
NOTE: Prior approved PSMA-targeted therapies \[e.g. 177Lu-PSMA-617\] and immunotherapy (including sipuleucel-T and immune checkpoint therapies) are permitted.
4. Have had either orchiectomy OR be on luteinizing hormone-releasing hormone (LHRH) agonist or antagonist therapy with serum testosterone \<50 ng/dL AND agree to stay on LHRH agonist or antagonist therapy during the study.
5. ECOG performance status (PS) grade of 0 or 1.
6. Adequate organ and bone marrow function documented by:
1. Hemoglobin .8.5 g/dL
2. Absolute neutrophil count .1.0 x 109/L
3. Platelet count .100 x 109/L
7. Serum creatinine .1.5 x ULN or estimated glomerular filtration rate \>50 mL/min/1.73 m2.
8. Adequate hepatic function:
1. Total bilirubin .1.5 x ULN
2. AST .2.5 x ULN
3. ALT .2.5 x ULN
4. Alkaline Phosphatase (ALP) .2.5 x ULN (.5 x ULN if tumor liver or bone involvement).
NOTES: Patients with Gilbert fs syndrome do not need to meet total bilirubin requirements provided their total bilirubin is not greater than their historical level. Gilbert fs syndrome must be documented appropriately as past medical history.
9. Consent to MD Anderson laboratory protocols PA13-0291 and Lab02-152.
10. Willing and able to comply with clinic visits and study-related procedures including provision of tumor tissue.
11. Provide informed consent signed by study patient.
12. To avoid risk of drug exposure through the ejaculate (even men with vasectomies), subjects must use a condom during sexual activity while on study drug and for 6 months following the last dose of study drug. If the subject is engaged in sexual activity with a woman of childbearing potential, a condom is required along with another effective contraceptive method consistent with local regulations regarding the use of birth control methods for subjects participating in clinical studies and their partners. Donation of sperm is not allowed while on study drug and for 6 months following the last dose of study drug.
5. Has received any previous systemic biologic therapy within 5 half-lives of first dose of study therapy.
NOTE: Prior treatment with sipuleucel-T is permitted
6. Patients who have not recovered (ie, grade .1 or baseline) from immune-mediated AEs 3 months prior to initiation of study drug therapy except for endocrinopathies adequately managed with hormone replacement.
7. Another malignancy that is progressing or requires active treatment, except:
1. Non-melanoma skin cancer that has undergone potentially curative therapy
2. Any tumor that has been deemed to be effectively treated with definitive local control (with or without continued adjuvant hormonal therapy)
8. Concurrent treatment with systemic corticosteroids (prednisone dose \>10 mg per day or equivalent) or other immunosuppressive drugs \<14 days prior to treatment initiation. Steroids that are topical, inhaled, nasal (spray), or ophthalmic solution are permitted.
9. History of or known or suspected autoimmune disease (exception(s): subjects with vitiligo, resolved childhood atopic dermatitis, hypothyroidism, or hyperthyroidism that is clinically euthyroid at screening are allowed).
10. Known evidence of an active infection requiring systemic therapy such as human immunodeficiency virus (HIV), active hepatitis, or fungal infection. Testing for hepatitis B and C infection will be performed at screening if not previously performed and documented.
11. History of clinically significant cardiovascular disease including, but not limited to:
* Myocardial infarction or unstable angina .6 months prior to treatment initiation
* Clinically significant cardiac arrhythmia
* Deep vein thrombosis, pulmonary embolism, stroke .6 months prior to treatment initiation
* Congestive heart failure (New York Heart Association class III-IV)
* Pericarditis/clinically significant pericardial effusion
* Myocarditis
12. Other prior malignancy (exceptions: adequately treated basal cell or squamous cell skin cancer, superficial bladder cancer, or any other cancer in situ currently in complete remission) .2 years prior to enrollment.
13. Encephalitis, meningitis, neurodegenerative disease (with the exception of mild dementia that does not interfere with activities of daily living \[ADLs\]) or uncontrolled seizures in the year prior to first dose of study therapy.
14. Known history of, or any evidence of interstitial lung disease, or active, non-infectious pneumonitis (past 5 years).
15. Receipt of a live vaccine within 4 weeks of planned start of study medication.
16. Prior allogeneic stem cell transplantation or recipients of organ transplants at any time, or autologous stem cell transplantation within 12 weeks of the start of study treatment.
17. Any medical, psychological or social condition that in the opinion of the investigator, would preclude participation in this study.
Exclusion Criteria
2. Has participated in a study of an investigational drug within 4-weeks of first dose of study therapy.
18 Years
MALE
No
Sponsors
Meet the organizations funding or collaborating on the study and learn about their roles.
Regeneron Pharmaceuticals
INDUSTRY
M.D. Anderson Cancer Center
OTHER
Responsible Party
Identify the individual or organization who holds primary responsibility for the study information submitted to regulators.
Principal Investigators
Learn about the lead researchers overseeing the trial and their institutional affiliations.
Bilal Siddiqui, MD
Role: PRINCIPAL_INVESTIGATOR
M.D. Anderson Cancer Center
Locations
Explore where the study is taking place and check the recruitment status at each participating site.
The University of Texas M. D. Anderson Cancer Center
Houston, Texas, United States
Countries
Review the countries where the study has at least one active or historical site.
Central Contacts
Reach out to these primary contacts for questions about participation or study logistics.
Facility Contacts
Find local site contact details for specific facilities participating in the trial.
Bilal Siddiqui, MD
Role: primary
Related Links
Access external resources that provide additional context or updates about the study.
MD Anderson Cancer Center Website
Other Identifiers
Review additional registry numbers or institutional identifiers associated with this trial.
NCI-2025-01092
Identifier Type: OTHER
Identifier Source: secondary_id
2024-0326
Identifier Type: -
Identifier Source: org_study_id